The clinical features of the piriformis syndrome: a systematic review

Piriformis syndrome, sciatica caused by compression of the sciatic nerve by the piriformis muscle, has been described for over 70 years; yet, it remains controversial. The literature consists mainly of case series and narrative reviews. The objectives of the study were: first, to make the best use of existing evidence to estimate the frequencies of clinical features in patients reported to have PS; second, to identify future research questions. A systematic review was conducted of any study type that reported extractable data relevant to diagnosis. The search included all studies up to 1 March 2008 in four databases: AMED, CINAHL, Embase and Medline. Screening, data extraction and analysis were all performed independently by two reviewers. A total of 55 studies were included: 51 individual and 3 aggregated data studies, and 1 combined study. The most common features found were: buttock pain, external tenderness over the greater sciatic notch, aggravation of the pain through sitting and augmentation of the pain with manoeuvres that increase piriformis muscle tension. Future research could start with comparing the frequencies of these features in sciatica patients with and without disc herniation or spinal stenosis

Effect of plasma proteins in friction of medical materials on PVA hydrogel

February 20th, 2014International audienceno abstrac

High-speed nanoscopic tracking of the position and orientation of a single virus.

Optical studies have revealed that, after binding, virions move laterally on the plasma membrane, but the complexity of the cellular environment and the drawbacks of fluorescence microscopy have prevented access to the molecular dynamics of early virus-host couplings, which are important for cell infection. Here we present a colocalization methodology that combines scattering interferometry and single-molecule fluorescence microscopy to visualize both position and orientation of single quantum dot-labeled Simian virus 40 (SV40) particles. By achieving nanometer spatial and 8 ms temporal resolution, we observed sliding and tumbling motions during rapid lateral diffusion on supported lipid bilayers, and repeated back and forth rocking between nanoscopic regions separated by 9 nm. Our findings suggest recurrent swap of receptors and viral pentamers as well as receptor aggregation in nanodomains. We discuss the prospects of our technique for studying virus-membrane interactions and for resolving nanoscopic dynamics of individual biological nano-objects